As I think I implied earlier, this particular subject is slightly over my head when it comes down to the technical details, but my design head can't quite drop the subject and shut my mouth and just be an audience member within this thread.
Aside from my concerns about the practical safety aspects for such a 'home-made' product/project using pressurized gas together with gasoline on a single-tracked vehicle along with all the associated vulnerabilities, my next area of questioning (devils advocate questioning) is the packaging implications (i.e. size, shape, volume).
What volume is required to house the amount of propane needed to achieve the range required?
I'm not familiar with the cross sectional profile of the 'older' model Rocket 111, but i've seen a section through the latest model fuel tank and there is far less available volume inside it than is apparent from it's overall appearance when fully fitted on the bike.
I'm guessing that the older model has a similar 'weakness' in this way.....and.....with the tank being even higher than on the latest model, it's going to be one hell of an interesting looking tank if you need a larger vessel volume for propane + gasoline.
Well my Deer Jagster
That's the purpose of doing pre-feasability and feasability studies: what can and cannot be done, and at what price.
As a reference there are kevlar fuel tanks built to store 300km (I think) for gaseous hydrogen at 600 or 700 bar for family automobile, and I believe Toyota has a purpose built car for H2. Propane would be only at 7 or 8 bars in a kevlar envelope, shaped by a carbon fiber (?) skeleton. Maybe it'll give less than 300km.
Propane and gascoline at such low pressures and temperatures are likely imiscible, and if ay propane disolves in the bit of gasoline in the bottom of the tank, then it will come out of solution (boil off) as the propane pressure drops near the end. What's interesting about this approach is you can fill the tank full of one, the other or some ratio, very elegant, at least on blog.
Cars converted to propane almost always keep a gasoline tank and you can switch from one fuel to the other on the fly.
So waddaya tink?
Fuel tank would keep same shape but a compete replacement. I simply wonder how the finish will look, and what buget the project would need. But we're early in te prefeasability. I think this project might be eligible for R&D $ support, as other projects I've done.
Please note that I'm a licensed professional engineer in good standing, working with a fast prototyping shop having many mechanical engineers with most recent tools like FEA, some CFD, etc. so this project does not really fall under a "home built" category, but engineered with resources of industrial flavour, not transportation or racing, which might be a better match. As a licensed professional engineer, and by ingrained habit, I must do a rigourous diligence. It's also a smart way not to re-invent the wheel and save money. Also in my view of the world 360° Risk and Opportunity assessments are part of this process. Finally I believe down to my bones that anybody can and may have a better idea than I, or a highly pertinent question.
THOSE are the reasons I highly value your input, and, especially, Devil's Advocate questions Jagster you've been riding R3s a lot longer than I, AND, are mechanically minded.
Please continue to advocate for the dark one so more possible issues be identified and tacked. Thanks !
xian